People with psoriasis may be at a higher risk of developing other conditions, including disorders affecting the thyroid gland.
A?study published in the?Journal of the American Academy of Dermatology?found that individuals with?psoriasis?were almost twice as likely to develop another autoimmune condition compared with those without psoriasis. Autoimmune disorders linked with psoriasis include?rheumatoid arthritis (RA),?alopecia areata,?celiac disease, scleroderma,?lupus,?Sj?gren's syndrome, and?thyroid disease.
“Autoimmune diseases frequently cluster,” says?Ana-Maria Orbai, MD,?director of the psoriatic arthritis program at Johns Hopkins Medicine in Baltimore. She has observed that frequency of thyroid disease is higher in women when another autoimmune disease, such as psoriasis, is present.
An Immune System Cell May Be the Common Culprit
A butterfly-shaped gland located in the neck just above the collarbone, the thyroid makes hormones and regulates heart and digestive function, mood, bone maintenance, calorie-burning, muscle control, and brain development.
A large retrospective study published in April 2019 in the Journal of the American Academy of Dermatology (JAAD)?found that individuals with psoriasis were at:
- 38 percent higher risk of hypothyroidism (an underactive thyroid gland)
- 47 percent higher risk of Hashimoto’s thyroiditis (the most common cause of hypothyroidism)
- 22 percent higher risk of having hyperthyroidism (an overactive thyroid gland)
- 26 percent higher risk of Graves’ disease (a disorder that causes hyperthyroidism)
“I have seen patients throughout the years with psoriasis and thyroid disease, mainly Hashimoto’s thyroid disorder and hypothyroidism,” says Spyros Mezitis, MD, an endocrinologist affiliated with Lenox Hill Hospital–Northwell Health and NewYork–Presbyterian Hospital and Cornell Medicine in New York City. “There may be a link related to T-helper 1 cells, which are part of our immune system and play a role in the process of these diseases.”
The research in JAAD suggested that thyroid problems and psoriasis may be explained by type 1 T-helper (TH1) cells, which play an important role in inflammatory response.
“They do share some of the same kind of T cells and T-cell response,” says Matthew Lewis, MD, a dermatologist with Stanford Health Care in Redwood City, California.
Dr. Lewis, however, points out that the connection between the two diseases may be due solely to chance because about 5 percent of the population has hypothyroidism, according to the National Institute of Diabetes and Digestive and Kidney Disease, while 2 to 3 percent have psoriasis, according to the National Psoriasis Foundation (NPF).
“By sheer statistical odds, a certain percent of the population is going to have both,” he says.
Psoriasis is also associated with many other health risks, such as diabetes and obesity, that could affect the thyroid, according to Lewis.
He adds that joint?guidelines published in April 2019 in the Journal of the American Academy of Dermatology by the JAAD and the NPF do not mention thyroid disease. “They leave it out of the discussion,” he says.
Keeping Tabs on Thyroid Health and Overall Wellness
Still, Lewis and Dr. Mezitis advise that psoriasis patients may want to have their thyroid health checked out.
“The evidence is a little bit weak now, so it hasn’t made it into the guidelines. But it makes sense to check the thyroid, and it will probably become part of the annual testing we do on psoriasis patients,” says Lewis.
Mezitis suggests that more research on the mechanisms driving the two diseases may reveal treatments for both.
“We don’t have a treatment for the two together, but more studies may show if psoriasis medication may help thyroid problems and if thyroid treatment may help psoriasis,” he says.
Some investigations, such as a study published in April 2019 in the journal Cardiovascular Research, have observed that the new biologics to treat psoriasis may reduce heart disease risk. Because biologics appear to have an anti-inflammatory effect, it may be possible that they could lower risk of thyroid disease as well, but more research is needed.
In addition to medication, Mezitis recommends certain lifestyle changes that may help reduce inflammation associated with either condition. These interventions include regular exercise, eating healthy, getting enough sleep, and reducing stress.
Diet and exercise promote weight loss, and dropping pounds can decrease symptoms of psoriasis,?according to the NPF. Fat releases the tumor necrosis factor protein, which is which is one of the main chemicals that worsens inflammation, according to past research.
“We know that weight loss is an effective intervention to reduce inflammation [as shown in studies like one published in 2018 in the journal Clinical Nutrition ESPEN],” says Lewis, “but it’s not at the forefront of our discussions with psoriasis patients.”
No matter if individuals have psoriasis, thyroid disease, or both, Mezitis urges them to seek a doctor’s care.
“People who have these diseases need to go a physician, be examined, and talk about specific lifestyle modifications and treatment,” he says.